1. Field of the Invention
The present invention relates to a bending joint mechanism used in a multidegree-of-freedom surgical instrument, a surgical instrument having this bending joint mechanism, and a manipulator having this bending joint mechanism.
2. Description of the Related Art
There has heretofore been known a joint drive device that uses wires to drive joint sections of a treatment instrument such as a multidegree-of-freedom surgical instrument. In this mechanism, problems occur in durability, maintenance, and controllability, such as stretching, loosening, or cutoff by fatigue of the wires. Moreover, in this mechanism, it is difficult to transmit power through bending joint portions to farther joints.
To solve this problem, for example, Jpn. Pat. Appln. KOKAI Publication No. 2008-307310 has disclosed a drive mechanism for driving a joint mechanism. The joint mechanism comprises a double rotation guide having two rolling guides. The drive mechanism serves as a translation cam mechanism which is driven, for example, by a parallel link or by a rack and pinion. Means shown in Jpn. Pat. Appln. KOKAI Publication No. 2008-307310 is provided with the two rolling contact guides, and a plate for bending which keeps the rotation centers of the guides at a distance and which rolls one guide, whereby a bending joint is obtained.
Furthermore, in this translation cam mechanism, a wire is put on a pulley around the rotation center of the guide. In this way, power is transmitted to a driven portion following the bending joint by the wire without interference with the operation of the bending joint.